I'm going to say that no plant deformation would be considered "normal." Some can be expected, but it is still and indication of a problem. I don't have any outdoor experience, so you will have to wait for more info... but to get a better answer you will want to let people know:

Strain (if you know it)
How big is it?
Soil type
Water schedule
Are you feeding it?
Container size
Direct sunlight during day or shaded and local climate?
What kind of light used at night?
What is indoor climate like?
In a box or an open room at night?
Any noticeable bugs?

Hmm... probably more, but that should set you on your way to effective solutions.

Hope that helps! :jointsmile:

Oh, and a picture is worth a thousand words... especially when troubleshooting plant problems. :thumbsup: